How the hell are we to be expected to overthrow a tyrannical government if we don't have RPGs though? Afghani freedom fighters can't even protect themselves against the US WITH RPGs and mortars, what the fuck are we going to do with just guns?
I hope that a decent amount of military will defect, bringing us armor, artillery, and other relatively portable, self-contained weaponry. I think that's what would win the second American Revolution.
I think the biggest obstacle would be aircraft. Harder to operate, more fragile, harder to maintain. Would likely remain a government tool.
Luckily, though, the largest weapons (large missiles, bombs, and whatnot) would probably be the least effective, since massive destruction would only serve to turn more of the populace against them. It would have to be war on our terms.
What's the point of speculating about a coup that will probably never happen (but should)?
This: I doubt a lack of select fire rifles, machineguns, or man-portable anti-tank weapons would have that large an impact in the grand scheme of things. A nation full of people wielding semi-auto small arms that are arguably as effective as your standard battle rifle (they don't see a whole lot of fullauto or burst use) probably isn't going to be taken lightly. I doubt a compliment of SAW's and sophisticated explosive devices (small ones, at least) would make that large a difference.
edit: even a new AWB wouldn't make much difference. We've already got the goods, and could do without them, anyhow. It's not like we're WWII Russia, trying to fight the blitzkrieg with Mosin-Nagants. That mini-14 will kill just as well as an M4/M16.
Which is part of the reason why such bans are so ill-concieved and, well, completely retarded.